Poly(I:C) source, molecular weight and endotoxin contamination affect dam and prenatal outcomes, implications for models of maternal immune activation

The viral mimetic polyinosinic:polycytidylic acid (poly(I:C)) is increasingly used to induce maternal immune activation (mIA) to model neurodevelopmental disorders (NDDs). Robust and reproducible phenotypes across studies are essential for the generation of models that will enhance our understanding of NDDs and enable the development of improved therapeutic strategies. However, differences in mIA-induced phenotypes using poly(I:C) have been widely observed, and this has prompted the reporting of useful and much needed methodological guidelines. Here, we perform a detailed investigation of molecular weight and endotoxin variations in poly(I:C) procured from two of the most commonly used suppliers, Sigma and InvivoGen. We demonstrate that endotoxin contamination and molecular weight differences in poly(I:C) composition lead to considerable variability in maternal IL-6 response in rats treated on gestational day (GD)15 and impact on fetal outcomes. Specifically, both endotoxin contamination and molecular weight predicted reductions in litter size on GD21. Further, molecular weight predicted a reduction in placental weight at GD21. While fetal body weight at GD21 was not affected by poly(I:C) treatment, male fetal brain weight was significantly reduced by poly(I:C), dependent on supplier. Our data are in agreement with recent reports of the importance of poly(I:C) molecular weight, and extend this work to demonstrate a key role of endotoxin on relevant phenotypic outcomes. We recommend that the source and batch numbers of poly(I:C) used should always be stated and that molecular weight variability and endotoxin contamination should be minimised for more robust mIA modelling.

Verification of long wavelength electromagnetic modes with a gyrokinetic-fluid hybrid model in the XGC code

As an alternative option to kinetic electrons, the gyrokinetic total-f particle-in-cell (PIC) code XGC1 has been extended to the MHD/fluid type electromagnetic regime by combining gyrokinetic PIC ions with massless drift-fluid electrons analogous to Chen and Parker [Phys. Plasmas 8, 441 (2001)]. Two representative long wavelength modes, shear Alfvén waves and resistive tearing modes, are verified in cylindrical and toroidal magnetic field geometries.

Fast Low-to-High Confinement Mode Bifurcation Dynamics in a Tokamak Edge Plasma Gyrokinetic Simulation

Transport barrier formation and its relation to sheared flows in fluids and plasmas are of fundamental interest in various natural and laboratory observations and of critical importance in achieving an economical energy production in a magnetic fusion device. Here we report the first observation of an edge transport barrier formation event in an electrostatic gyrokinetic simulation carried out in a realistic diverted tokamak edge geometry under strong forcing by a high rate of heat deposition. The results show that turbulent Reynolds-stress-driven sheared E×B flows act in concert with neoclassical orbit loss to quench turbulent transport and form a transport barrier just inside the last closed magnetic flux surface.

Ten-year cardiovascular risk assessment in university students

Cardiovascular disease (CVD) is responsible for more than half of all deaths in the European region. The aim of the study was to compare body composition, blood pressure, total cholesterol (TC) and high density lipoprotein cholesterol (HDL-C), family history, activity behaviors, and the 10-year risk of having a heart attack between 166 university students (21.62 ± 2.59 yrs) from Utah (USA) and 198 students (22.11 ± 2.51 yrs) from Hungary. Ninety-two percent of the Hungarian students and 100% of the Utah students had an estimated 10-year Framingham risk score of 1% or less. The high prevalence of low risk was primarily due to the young age of study participants, healthy body composition and non-smoking behavior. Hungarians who had higher 10-year risk of heart attack had significantly higher waist hip ratio (WHR), TC, diastolic blood pressure (DBP) and were smokers compared to those Hungarians with lower risk. The self-reported physical activity levels between the two groups of students were not different. In conclusion the young men and women who participated in this study were, for the most part healthy; however the smoking habits and the lower physical activity of the Hungarian students likely elevated their risk of CVD.

Nonlinear dispersion relation of geodesic acoustic modes

The energy input and frequency shift of geodesic acoustic modes (GAMs) due to turbulence in tokamak edge plasmas are investigated in numerical two-fluid turbulence studies. Surprisingly, the turbulent GAM dispersion relation is qualitatively equivalent to the linear GAM dispersion but can have drastically enhanced group velocities. In up-down asymmetric geometry the energy input due to turbulent transport may favor the excitation of GAMs with one particular sign of the radial phase velocity relative to the magnetic drifts and may lead to pulsed GAM activity.

Genotype-dependent responses to levels of sibling competition over maternal resources in mice

Research on phenotypic plasticity has often focused on how a given genotype responds to the changing physical environments such as temperature or diet. However, for many species the social environment has an equally important role because of competition for resources. During early development, the level of competition for limited (maternally provided) resources will often depend critically on the number of siblings. Therefore, competition among siblings should drive the evolution of genes that allow flexible responses to realized levels of competition and maternal resource availability. However, it is unknown whether genetically based differences between individuals exist in their response to the social environment that affect their future development. Using a quantitative trait locus approach in an experimental population of mice we demonstrate that effects of sibling number on body weight depend on individual genotype at seven loci, over and above the general negative litter size effect. Overall, these litter size-by-genotype interactions considerably modified the degree to which increasing litter size caused reduced weight. For example at one locus this effect leads to a 7% difference in body weight at week 7 between individuals experiencing the extremes of the normal range of litter sizes in our population (five to nine litter mates). The observed interaction between genotype and the competitive environment can produce differences in body weight that are similar in magnitude to the main effect of litter size on weight. Our results show that different genotypes respond to the social environment differentially and that interaction effects of genotype with litter size can be as important as genotype-independent effects of litter size.

Selective abortion and the evolution of genomic imprinting

Mothers can determine which genotypes of offspring they will produce through selective abortion or selective implantation. This process can, at some loci, favour matching between maternal and offspring genotype whereas at other loci mismatching may be favoured (e.g. MHC, HLA). Genomic imprinting generally renders gene expression monoallelic and could thus be adaptive at loci where matching or mismatching is beneficial. This hypothesis, however, remains unexplored despite evidence that loci known to play a role in genetic compatibility may be imprinted. We develop a simple model demonstrating that, when matching is beneficial, imprinting with maternal expression is adaptive because the incompatible paternal allele is not detected, protecting offspring from selective abortion. Conversely, when mismatching is beneficial, imprinting with paternal expression is adaptive because the maternal genotype is more able to identify the presence of a foreign allele in offspring. Thus, imprinting may act as a genomic 'cloaking device' during critical periods in development when selective abortion is possible.

Sit to stand transfer: performance in rising power, transfer time and sway by age and sex in senior athletes

OBJECTIVE

To observe the differences in performance variables of the sit to stand transfer (as measured on the NeuroCom Balance Master) in a population of senior athletes.

METHOD

A convenience sample of 173 subjects aged 50 years and older. Data were obtained from voluntary participation in a health fair offered at the annual Huntsman World Senior Games in St George, Utah, USA. All sit to stand tests were performed on the NeuroCom Balance Master. The measured parameters were weight transfer time (WTT), rising power (force exerted to rise), and centre of gravity sway (COG sway) during the rising phase.

RESULTS

A significant difference was found between stratified age groups (50-64 and 65+ years) on rising power. There was also a sex difference in rising power. No significant differences were found in weight transfer time or COG sway.

CONCLUSION

While rising power decreases with increasing age in senior athletes, WTT and COG sway remain similar regardless of age or sex. The maintenance of these other two variables (WTT and COG sway) may be attributable to physical activity and/or participation in sport.

Mitochondria suppress local feedback activation of inositol 1,4, 5-trisphosphate receptors by Ca2+

The concerted action of inositol 1,4,5-trisphosphate (IP3) and Ca2+ on the IP3 receptor Ca2+ release channel (IP3R) is a fundamental step in the generation of cytosolic Ca2+ oscillations and waves, which underlie Ca2+ signaling in many cells. Mitochondria appear in close association with regions of endoplasmic reticulum (ER) enriched in IP3R and are particularly responsive to IP3-induced increases of cytosolic Ca2+ ([Ca2+]c). To determine whether feedback regulation of the IP3R by released Ca2+ is modulated by mitochondrial Ca2+ uptake, the interactions between ER and mitochondrial Ca2+ pools were examined by fluorescence imaging of compartmentalized Ca2+ indicators in permeabilized hepatocytes. IP3 decreased luminal ER Ca2+ ([Ca2+]ER), and this was paralleled by an increase in mitochondrial matrix Ca2+ ([Ca2+]m) and activation of Ca2+-sensitive mitochondrial metabolism. Remarkably, the decrease in [Ca2+]ER evoked by submaximal IP3 was enhanced when mitochondrial Ca2+ uptake was blocked with ruthenium red or uncoupler. Moreover, subcellular regions that were relatively deficient in mitochondria demonstrated greater sensitivity to IP3 than regions of the cell with a high density of mitochondria. These data demonstrate that Ca2+ uptake by the mitochondria suppresses the local positive feedback effects of Ca2+ on the IP3R, giving rise to subcellular heterogeneity in IP3 sensitivity and IP3R excitability. Thus, mitochondria can play an important role in setting the threshold for activation and establishing the subcellular pattern of IP3-dependent [Ca2+]c signaling.

Preservation of viable biological samples for experiments in space laboratories

Standard viable preservation methods for biological samples using low temperatures have been investigated concerning their storage capabilities under higher temperature levels than usual. For a representative set of organism classes (plants, mammalian cells, arthropods and aquatic invertebrates), the minimum appropriate storage conditions have been identified by screening storage temperatures at -196 degrees, -80 degrees, -20 degrees, +4 degrees, +20 degrees/25 degrees C for periods from 2 days to 4 weeks. For storage below 0 degree C, as a typical cryopreservative, dimethylsulfoxide (DMSO) was used. For some samples, the addition of trehalose (as cryopreservative) and the use of a nitrogen atmosphere were investigated. After storage, the material was tested for vitality. The findings demonstrated that acceptable preservation can be achieved under higher storage temperatures than are typically applied. Small, dense cultured plant cells survive for 21 d when moderately cooled (+4 degrees to -20 degrees C); addition of trehalose enhances viability at -20 degrees C. For mammalian cells, the results show that human lymphocytes can be preserved for 3 d at 25 degrees C, 7 d at 4 degrees C and 28 d at -80 degrees C. Friend leukaemia virus transformed cells can be stored for 3 d at 25 degrees C, 14 d at 4 degrees C and 28 d at -80 degrees C. Hybridoma cells can be kept 7 d at 4 degrees C and 28 d at -20 degrees C or -80 degrees C. Model arthropod systems are well preserved for 2 weeks if maintained at lower temperatures that vary depending on the species and/or stage of development; e.g., 12 degrees C for Drosophila imagoes and 4-6 degrees C for Artemia nauplii. For aquatic invertebrates such as sea urchins, embryonic and larval stages can be preserved for several weeks at +6 degrees C, whereas sperm and eggs can best be stored at + 4 degrees C for up to 5 d at maximum. These results enhance the range of feasible space experiments with biological systems. Moreover, for typical terrestrial preservation methods, considerable modification potential is identified.

Halothane regulates G-protein-dependent phospholipase C activity in turkey erythrocyte membranes

The ability of halothane to stimulate phospholipase C (PLC) was examined in turkey erythrocyte membranes prepared from [3H]inositol-labeled turkey erythrocytes by measuring [3H]inositol phosphate formation ([3H]InsP) in the presence and absence of G-protein activation. In the presence of guanosine 5'-3-O-(thio)triphosphate) (GTP gamma S), halothane (0.5-10 mM) caused a dose-dependent activation of PLC. The EC50 value for halothane-induced PLC activation was 2.8 +/- 0.3 mM. Halothane (0.1-30 mM) had no effect on PLC activity in the absence of G-protein activation and did not affect Ca(2+)-dependent PLC activity. The activation of PLC by GTP gamma S occurred after an initial lag period of 60 s which was followed by a linear increase in [3H]InsP. Halothane dose-dependently decreased the lag period for GTP gamma S-induced PLC activation (minimal value 15 s) and increased the rate of [3H]InsP formation at all time points following this lag. As a result, halothane shifted the EC50 value for GTP gamma S-induced PLC activation to the left (4-fold) and increased its maximal response. Halothane also caused a dose-dependent activation of PLC in the presence of AlF4-. Half-maximal stimulation of AlF4(-)-activated PLC occurred with an EC50 value of 2.9 +/- 0.4 mM halothane, which is similar to the halothane dose giving half-maximal stimulation of PLC in the presence of GTP gamma S. At low doses (0.1-0.3 mM) halothane inhibited both isoproterenol- and adenosine 5'-O-(2-thiodiphosphate) (ADP beta S)-induced [3H]InsP formation, whereas at higher concentrations it stimulated PLC independent of the presence of these agonists. At concentrations chosen to reflect their different membrane/buffer partition coefficients, both hexanol (5 mM) and benzyl alcohol (20 mM) fluidized turkey erythrocyte membranes to the same degree as halothane (5 mM). However, these agents had no effect on GTP gamma S- or AlF(4-)-induced PLC activity, indicating that halothane-induced PLC activation was not secondary to changes in bulk lipid fluidity properties. Halothane also stimulated [3H]inositol bisphosphate and [3H]inositol trisphosphate formation in intact erythrocytes. These data demonstrate that the anesthetic halothane can stimulate G-protein-dependent PLC activity and modify the responsiveness of this signaling system to activation by receptor-linked agonists.

Beta-adrenergic receptor-mediated phospholipase C activation independent of cAMP formation in turkey erythrocyte membranes

The effect of the beta-adrenergic receptor agonist isoproterenol on guanine nucleotide-dependent phospholipase C (PLC) activity was examined in turkey erythrocyte membranes prepared from [3H]inositol-labeled turkey erythrocytes. In the presence of guanosine 5'-(gamma-thiotriphosphate) (GTP[S]) isoproterenol caused a dose-dependent stimulation of [3H]inositol phosphate ([3H]InsP) formation. The activation of PLC by GTP[S] occurred after an initial lag period of 1-2 min and was followed by a sustained rate of [3H]InsP formation which remained linear for 4-5 min. Isoproterenol decreased the lag period for GTP[S]-induced [3H]InsP formation and increased PLC activity at all time points following this lag. Consequently, isoproterenol shifted the dose-response curve for GTP[S] to the left (10-fold) and increased the maximal response. The EC50 value for isoproterenol-induced activation of PLC was 104 +/- 17 nM. Isoproterenol also potentiated GTP-dependent PLC activity but was ineffective in stimulating the enzyme in the presence of AIF4-. The PLC activation by isoproterenol was completely inhibited by propanolol and atenolol but was unaffected by prazosin or yohimbine. Although GTP[S] and isoproterenol could increase cAMP formation in this membrane preparation, the isoproterenol-induced stimulation of PLC occurred in the absence of ATP and was independent of cAMP formation. Furthermore, addition of cAMP, 8-bromo-cAMP, forskolin, or either the regulatory or catalytic subunits of cAMP-dependent protein kinase failed to stimulate [3H]InsP formation and had no effect on the responses elicited by GTP[S] and isoproterenol. Isoproterenol also stimulated [3H]InsP2 and [3H]InsP3 production in intact erythrocytes. Cholera toxin had no effect on [3H]InsP formation in the intact cells under conditions where it stimulated cAMP accumulation. In addition, the activation of PLC by GTP[S] and isoproterenol was unaffected in membranes prepared from cholera toxin-treated erythrocytes. These data demonstrate that stimulation of turkey erythrocyte beta-adrenergic receptors by isoproterenol results in a direct activation of guanine nucleotide-dependent PLC.

Validity and reliability of an ultrasound device for detecting carotid emboli

Cardioembolic mechanisms cause 15 to 20% of all strokes and may account for the high incidence of neurological dysfunction associated with cardiopulmonary bypass. Accurate identification of high-risk subjects and/or surgical techniques would allow more effective testing and implementation of preventive or therapeutic measures to help reduce morbidity and mortality. This article reports on validity and reliability testing of a new emboli detection device that allows continuous monitoring of the common carotid artery. The instrument appears to be capable of detecting accurately particles of 193 mu or less in diameter and is highly reliable both within and between observers. In preliminary clinical use, the instrument also detected embolic signals in all patients monitored during cardiopulmonary bypass, while none were detected in healthy control subjects. These results establish the validity and reliability of a new emboli detection device and suggest its potential application to emboli detection monitoring during cardiopulmonary bypass.

Short chain alcohols activate guanine nucleotide-dependent phosphoinositidase C in turkey erythrocyte membranes

The ability of alcohols to regulate inositol lipid-specific phospholipase C (phosphoinositidase C) was examined in turkey erythrocyte ghosts prepared by cell lysis of erythrocytes which were prelabeled with [3H] inositol. Guanosine 5'-[gamma-thiotriphosphate] GTP[S] stimulated the production of both [3H]inositol bisphosphate (18-fold) and [3H]inositol trisphosphate (6-fold) in this system. The accumulation of [3H]inositol bisphosphate and [3H]inositol trisphosphate was linear up to 8 min following an initial lag period of 1-2 min. Ethanol (300 mM) reduced the lag period for [3H]inositol phosphate accumulation at submaximal GTP[S] concentrations and caused a shift to the left (3-fold) in the dose-response curve. Other short chain alcohols, methanol (300 mM), 1-propanol (200 mM), and 1-butanol (50 mM) also enhanced the accumulation of [3H] inositol phosphates in the presence of submaximal GTP[S] concentrations. Receptor activation by the purinergic agonist adenosine 5'-[beta-thio]disphosphate (ADP[S]) (10 microM) also reduced the lag period for [3H] inositol phosphate formation and shifted the GTP[S] dose response to the left (10-fold). In addition, ADP[S] increased the response to maximal GTP[S] concentrations. The formation of [3H]inositol phosphates induced by GTP[S] was associated with a concomitant decrease in labeling of both [3H]phosphatidylinositol monophosphate and [3H]phosphatidylinositol bisphosphate, but no decrease in [3H]phosphatidylinositol was observed. All of the alcohols tested enhanced the breakdown of [3H]polyphosphoinositides in the presence of GTP[S]. The dose response to guanosine 5'-[beta gamma-imino]triphosphate for [3H]inositol phosphate formation was displaced to the left by ethanol (300 mM) and ADP[S] (10 microM) (2- and 7-fold), respectively. ADP[S] also enhanced the maximal response to guanosine 5'-[beta gamma-imino]triphosphate. The [3H]inositol phosphate formation produced in response to NaF was unaffected by either ethanol or receptor activation. These results indicate that alcohols initiate an activation of phosphoinositidase C, mediated at the level of the regulatory guanine nucleotide-binding protein.

Lymphocyte subpopulations before therapy in patients with uveal malignant melanoma

T-cell and B-cell lymphocyte subpopulations, monocytes, granulocytes, and immunoglobulin receptors were measured with monoclonal antibodies and flow cytometric techniques in the peripheral blood of 266 patients with posterior uveal melanoma before therapy. Statistically significant differences were found in T-helper/inducer (OKT4), T-suppressor/cytotoxic (OKT8), and B-lymphocyte populations between patients with uveal melanoma and age-matched controls.